This invention generally relates to systems and methods for processing blood and other biological fluids.
FIG. 1 shows a typical disposable bag set used in the prior art to process blood. The set includes a needle 10 or cannula, which is inserted into a vein of a donor. The needle 10 is connected to the tube 11, which in turn is connected to collection bag 12, so as to allow whole blood to flow from the donor through the needle 10 and the tube 11 into collection bag 12. The collection bag 12 contains anticoagulant. After the desired amount of blood has been collected into collection bag 12, the needle 10 is removed from the donor, and tube 11 is cut and heat sealed. The remainder of the bag set is then brought to a centrifuge, which spins the bag set so that the blood in collection bag 12 separates into plasma and red blood cells. Typically, the centrifuge is not located at the point where the blood donation takes place.
After the blood has separated into plasma and red blood cells (RBCs), the bag set is removed from the centrifuge. The plasma component is urged from collection bag 12 through tube 13 into plasma-storage bag 14. The tube leading to the plasma-storage bag 14 is then cut and heat sealed. Storage-solution bag 16 holds RBC-storage solution. After the plasma component has been urged into the plasma-storage bag 14, the RBC-storage solution is urged from the storage-solution bag 16 into the collection bag 12. Tube 13 is then cut and heat sealed.
The remaining portion of the bag set consists of the collection bag 12, which now holds primarily RBCs (along with storage solution), filter 17, RBC-storage bag 18, and the tubing that connects these components. The collection bag 12 is then hung, so that gravity causes the RBC component to pass through the filter 17 to RBC-storage bag 18. The filter 17 removes white blood cells (WBCs) from the RBCs. After the RBCs (and storage solution) pass into the RBC-storage bag 18, tube 19 is cut and heat sealed.
This prior-art process of collecting and separating blood components involves many steps and frequent human intervention. The arrangement of the prior-art bag set does not permit the process to be easily automated.
The present invention is directed to systems and methods for collecting blood components, and in particular, systems and methods that reduce the need for human intervention.
In a preferred embodiment, a disposable set is provided having a port, an RBC container, a centrifuge rotor having a variable total volume, and a filter, along with tubing connecting the port, the container, the rotor and the filter. A control unit is also provided. The control unit preferably includes a spinner in which the rotor may be held, a flow-control arrangement for controlling flow among the various components of the disposable set, and an electronic controller.
The controller may be used to control the spinner and the flow-control arrangement.
Preferably, the rotor is placed in the spinner, before whole blood is drawn through the port. The port is preferably a needle or other cannula inserted into a vein of the donor. The whole blood is directed by the flow-control arrangement from the port through the tubing to the rotor. In a preferred embodiment, the rotor includes a flexible diaphragm, and the control unit""s flow-control arrangement includes a pump or other device for applying a negative pressure to the rotor""s flexible diaphragm, so as to draw fluid into the rotor. The rotor is also preferably provided with a fixed portion, a rotatable portion and a rotary seal providing a seal between the fixed and rotatable portions, and the tubing may be connected to the rotor""s fixed portion.
The spinner rotates the rotor so as to separate the whole blood into a first component and a second component, wherein the first component is primarily plasma, and wherein the second component is primarily red blood cells (RBCs) and includes white blood cells (WBCs). Preferably, the first component, the plasma, is urged out of the rotor first, while the rotor is still being spun to keep the first and second components separated. In one preferred embodiment, the needle is removed from the donor before any of the components are urged from the rotor. The plasma is preferably directed to and stored in a plasma-storage container. After the plasma has been removed from the rotor, the second component, containing red blood cells and white blood cells is urged from the rotor through the filter, so that white blood cells are caught in the filter and red blood cells pass through the filter. After passing through the filter, the red blood cells are stored in an RBC container.
In alternative preferred embodiments, a cannula remains in the donor so as to return the plasma component to the donor. Two separate cannulas may be used for drawing whole and returning the plasma component. In a preferred embodiment, a single cannula is used to draw whole blood and to return the plasma component; in this embodiment, a temporary storage container is used to hold the plasma while whole blood is being collected, and the plasma is returned when the red blood cells are being processed by and urged from the rotor.